Faeces were counted along horizontal, 5.0 m wide strips at altitude intervals of 100 m to examine the altitudinal ranging pattern of a band of black-and-white snub-nosed monkeys (Rhinopithecus bieti) at Nanren (99° 04’E, 28° 34’N, Baima Snow Mountain Nature Reverse, Yunnan, China) at four areas in each season between 2000-2001. Faeces were also counted along vertical, 2.5 m wide strips in one subvalley and on one subridge in each area. Monkeys used an altitudinal range of 3500-4300 m, but preferred occupying the upper forest belt between 3900 and 4200 m asl year-round, being at the highest altitude in summer, the lowest altitude in spring, and middle altitudes between autumn and winter (lower in winter than autumn). Moreover, there were secondary peaks of lower altitude use (3700 m) in spring and winter. In addition, more faeces were distributed in subvalleys than on subridges in winter, this suggests that monkeys tend to spend more time in subvalleys where there is less wind and fluctuating temperatures. The significant correlation between faecal density and lichen load might indicate that altitudinal distribution of food resources may act as an important factor affecting the monkeys’ range. The monkeys might migrate to lower altitudes to eat young sprouts and leaves in spring, and to shelter from snowstorms in winter, possibly resulting in the secondary peaks at lower altitudes.